---
title: "Dynamic load provider"
---

# Dynamic load provider


Modern.js provides [Data Loader](https://modernjs.dev/en/guides/basic-features/data/data-fetch.html#data-loader-recommended) to help For data management, `Data Loader` is only executed on the server side and will not be executed repeatedly on the client side.

This chapter will introduce how to use `Data Loader` to obtain producer information and load it dynamically.

## Create provider

Create a new provider for dynamic load.

### 1. Create configuration file

Create a `module-federation.config.ts` file in the project root directory and write the following content:

```ts title='module-federation.config.ts'
import { createModuleFederationConfig } from '@module-federation/modern-js';

export default createModuleFederationConfig({
  name: 'dynamic_provider',
  filename: 'remoteEntry.js',
  exposes: {
    './Image': './src/components/Image.tsx',
  },
  shared: {
    react: { singleton: true },
    'react-dom': { singleton: true },
  },
});
```

### 2. Apply plugin

Apply `@module-federation/modern-js` in `modern.config.ts`:

```ts title='modern.config.ts'
import { appTools, defineConfig } from '@modern-js/app-tools';
import { moduleFederationPlugin } from '@module-federation/modern-js';

// https://modernjs.dev/en/configure/app/usage
export default defineConfig({
  runtime: {
    router: true,
  },
  server: {
    ssr: {
      mode: 'stream',
    },
    port: 3008,
  },
  plugins: [appTools(), moduleFederationPlugin()],
});
```

### 3. Create need to be exposed component

Create the file `src/components/Image.tsx` with the following content:

```tsx title='Image.tsx'
import React from 'react';
import styles from './Image.module.css';

export default (): JSX.Element => (
  <div
    id="remote-components"
    style={{
      backgroundColor: '#c0e91e',
      color: 'lightgrey',
      padding: '1rem',
    }}
  >
    <h2>
      <strong>dynamic remote</strong>&nbsp;image
    </h2>
    <button
      id="dynamic-remote-components-button"
      style={{ marginBottom: '1rem' }}
      onClick={() => alert('[remote-components] Client side Javascript works!')}
    >
      Click me to test i'm interactive!
    </button>
    <img
      id="dynamic-remote-components-image"
      src="https://module-federation.io/module-federation-logo.svg"
      style={{ width: '100px' }}
      alt="serge"
    />
    <button className={styles['button']}>Button from dynamic remote</button>
  </div>
);
```

And create the corresponding style file, the content is as follows:

```css title='Image.module.css'
.button {
  background: red;
}
```

## Create loader

Create a `.data` file with the same name in the corresponding routing file. Taking the root directory `src/routes/page.tsx` as an example, create `src/routes/page.data.ts`:

```ts title='page.data.ts'
import { LoaderFunctionArgs } from '@modern-js/runtime/router';

export type DataLoaderRes = {
    providerList: Array<{
        name: string,
        entry: string,
        id: string;
    }>
}

const fetchProviderList = async () => {
    const res = await new Promise(resolve => {
        setTimeout(() => {
            resolve([
                {
                    name: 'dynamic_provider',
                    entry: 'http://localhost:3008/mf-manifest.json',
                    id: 'dynamic_provider/Image'
                }
            ])
        }, 1000);
    });

    return res as DataLoaderRes['providerList']
}

export const loader = async ({ request }: LoaderFunctionArgs): Promise<DataLoaderRes> => {
    console.log('request params', request);
    const providerList = await fetchProviderList();
    return {
        providerList
    }
};
```

## Load dynamic provider

Consume loader data and dynamically load the corresponding producer:

```tsx
import { loadRemote, registerRemotes, getInstance } from '@module-federation/modern-js/runtime';
import { createLazyComponent } from '@module-federation/modern-js/react';
// Use import type to get data loader types
import type { DataLoaderRes } from './page.data';
import { useLoaderData } from '@modern-js/runtime/router';

import './index.css';

const RemoteSSRComponent = createLazyComponent({
  instance: getInstance(),
  loader: () => import('remote/Image'),
  loading: 'loading...',
  export: 'default',
  fallback: ({ error }) => {
    if (error instanceof Error && error.message.includes('not exist')) {
      return <div>fallback - not existed id</div>;
    }
    return <div>fallback</div>;
  },
});

const Index = () => {
  // get data loader response
  const dataLoader = useLoaderData() as DataLoaderRes;
  // register dynamic remotes before loading them
  registerRemotes(dataLoader.providerList);

  const DynamicRemoteSSRComponents = dataLoader.providerList.map(item => {
    const { id } = item;
    const Com = createLazyComponent({
      instance: getInstance(),
      loader: () => loadRemote(id),
      loading: 'loading...',
      fallback: ({ error }) => {
        if (error instanceof Error && error.message.includes('not exist')) {
          return <div>fallback - not existed id</div>;
        }
        return <div>fallback</div>;
      },
    });
    return <Com />
  })
  return (
    <div className="container-box">
      <RemoteSSRComponent />
      {DynamicRemoteSSRComponents}
    </div>
  );
}

export default Index;
```
